Samoilys Melita A, Halford Andrew, Osuka Kennedy
CORDIO East Africa Mombasa Kenya.
Department of Zoology University of Oxford Oxford UK.
Ecol Evol. 2019 Mar 21;9(7):4149-4167. doi: 10.1002/ece3.5044. eCollection 2019 Apr.
Understanding the drivers of the structure of coral reef fish assemblages is vital for their future conservation. Quantifying the separate roles of natural drivers from the increasing influence of anthropogenic factors, such as fishing and climate change, is a key component of this understanding. It follows that the intrinsic role of historical biogeographical and geomorphological factors must be accounted for when trying to understand the effects of contemporary disturbances such as fishing.
Comoros, Madagascar, Mozambique and Tanzania, Western Indian Ocean (WIO).
We modeled patterns in the density and biomass of an assemblage of reef-associated fish species from 11 families, and their association with 16 biophysical variables.
Canonical analysis of principal coordinates revealed strong country affiliations of reef fish assemblages and distance-based linear modeling confirmed geographic location and reef geomorphology were the most significant correlates, explaining 32% of the observed variation in fish assemblage structure. Another 6%-8% of variation was explained by productivity gradients (chl_), and reef exposure or slope. Where spatial effects were not significant between mainland continental locations, fishing effects became evident explaining 6% of the variation in data. No correlation with live coral was detected. Only 37 species, predominantly lower trophic level taxa, were significant in explaining differences in assemblages between sites.
Spatial and geomorphological histories remain a major influence on the structure of reef fish assemblages in the WIO. Reef geomorphology was closely linked to standing biomass, with "ocean-exposed" fringing reefs supporting high average biomass of ~1,000 kg/ha, while "lagoon-exposed fringing" reefs and "inner seas patch complex" reefs yielded substantially less at ~500kg/ha. Further, the results indicate the influence of benthic communities on fish assemblages is scale dependent. Such insights will be pivotal for managers seeking to balance long-term sustainability of artisanal reef fisheries with conservation of coral reef systems.
了解珊瑚礁鱼类群落结构的驱动因素对于其未来的保护至关重要。量化自然驱动因素与人为因素（如捕鱼和气候变化）日益增加的影响所起的不同作用，是这一认识的关键组成部分。因此，在试图理解捕鱼等当代干扰的影响时，必须考虑历史生物地理和地貌因素的内在作用。
科摩罗、马达加斯加、莫桑比克和坦桑尼亚，西印度洋（WIO）。
我们对11个科的与珊瑚礁相关鱼类物种组合的密度和生物量模式及其与16个生物物理变量的关联进行了建模。
主坐标的典型分析揭示了珊瑚礁鱼类群落与国家的紧密联系，基于距离的线性建模证实地理位置和珊瑚礁地貌是最显著的相关因素，解释了观察到的鱼类群落结构变化的32%。另外6%-8%的变化由生产力梯度（chl_）、珊瑚礁暴露程度或坡度解释。在大陆地点之间空间效应不显著的地方，捕鱼效应变得明显，解释了数据中6%的变化。未检测到与活珊瑚的相关性。只有37种鱼类（主要是低营养级类群）在解释不同地点之间群落差异方面具有显著性。
空间和地貌历史仍然是西印度洋珊瑚礁鱼类群落结构的主要影响因素。珊瑚礁地貌与现存生物量密切相关，“面向海洋”的边缘礁平均生物量较高，约为1000千克/公顷，而“面向泻湖的边缘”礁和“内海斑块复合体”礁的生物量则显著较低，约为500千克/公顷。此外，结果表明底栖生物群落对鱼类群落的影响取决于尺度。这些见解对于寻求平衡手工珊瑚礁渔业的长期可持续性与珊瑚礁系统保护的管理者来说至关重要。
